/*
* Copyright (c) 2006-2007 Erin Catto http:
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* Converted for The Render Engine v2.0
* Aug. 4, 2010 Brett Fattori
*/

Engine.include("/physics/common/math/b2Math.js");
Engine.include("/physics/common/math/b2Vec2.js");

Engine.include("/physics/collision/ClipVertex.js");

Engine.initObject("b2Collision", null, function() {
   
   var b2Collision = Base.extend({
   
      constructor: null,

      b2_nullFeature: 0x000000ff,
      
      ClipSegmentToLine: function(vOut, vIn, normal, offset) {
         // Start with no output points
         var numOut = 0;

         var vIn0 = vIn[0].v;
         var vIn1 = vIn[1].v;

         // Calculate the distance of end points to the line
         var distance0 = b2Math.b2Dot(normal, vIn[0].v) - offset;
         var distance1 = b2Math.b2Dot(normal, vIn[1].v) - offset;

         // If the points are behind the plane
         if (distance0 <= 0.0) vOut[numOut++] = vIn[0];
         if (distance1 <= 0.0) vOut[numOut++] = vIn[1];

         // If the points are on different sides of the plane
         if (distance0 * distance1 < 0.0)
         {
            // Find intersection point of edge and plane
            var interp = distance0 / (distance0 - distance1);
            // expanded for performance
            var tVec = vOut[numOut].v;
            tVec.x = vIn0.x + interp * (vIn1.x - vIn0.x);
            tVec.y = vIn0.y + interp * (vIn1.y - vIn0.y);
            if (distance0 > 0.0)
            {
               vOut[numOut].id = vIn[0].id;
            }
            else
            {
               vOut[numOut].id = vIn[1].id;
            }
            ++numOut;
         }

         return numOut;
      },
      
      EdgeSeparation: function(poly1, edge1, poly2) {
         var vert1s = poly1.m_vertices;
         var count2 = poly2.m_vertexCount;
         var vert2s = poly2.m_vertices;

         // Convert normal from into poly2's frame.
         //b2Settings.b2Assert(edge1 < poly1.m_vertexCount);

         //var normal = b2Math.b2MulMV(poly1.m_R, poly1->m_normals[edge1]);
         var normalX = poly1.m_normals[edge1].x;
         var normalY = poly1.m_normals[edge1].y;
         var tX = normalX;
         var tMat = poly1.m_R;
         normalX = tMat.col1.x * tX + tMat.col2.x * normalY;
         normalY = tMat.col1.y * tX + tMat.col2.y * normalY;
         // ^^^^^^^ normal.MulM(poly1.m_R);

         //var normalLocal2 = b2Math.b2MulTMV(poly2.m_R, normal);
         var normalLocal2X = normalX;
         var normalLocal2Y = normalY;
         tMat = poly2.m_R;
         tX = normalLocal2X * tMat.col1.x + normalLocal2Y * tMat.col1.y;
         normalLocal2Y = normalLocal2X * tMat.col2.x + normalLocal2Y * tMat.col2.y;
         normalLocal2X = tX;
         // ^^^^^ normalLocal2.MulTM(poly2.m_R);

         // Find support vertex on poly2 for -normal.
         var vertexIndex2 = 0;
         var minDot = Number.MAX_VALUE;
         for (var i = 0; i < count2; ++i)
         {
            //var dot = b2Math.b2Dot(vert2s[i], normalLocal2);
            var tVec = vert2s[i];
            var dot = tVec.x * normalLocal2X + tVec.y * normalLocal2Y;
            if (dot < minDot)
            {
               minDot = dot;
               vertexIndex2 = i;
            }
         }

         //b2Vec2 v1 = poly1->m_position + b2Mul(poly1->m_R, vert1s[edge1]);
         tMat = poly1.m_R;
         var v1X = poly1.m_position.x + (tMat.col1.x * vert1s[edge1].x + tMat.col2.x * vert1s[edge1].y)
         var v1Y = poly1.m_position.y + (tMat.col1.y * vert1s[edge1].x + tMat.col2.y * vert1s[edge1].y)

         //b2Vec2 v2 = poly2->m_position + b2Mul(poly2->m_R, vert2s[vertexIndex2]);
         tMat = poly2.m_R;
         var v2X = poly2.m_position.x + (tMat.col1.x * vert2s[vertexIndex2].x + tMat.col2.x * vert2s[vertexIndex2].y)
         var v2Y = poly2.m_position.y + (tMat.col1.y * vert2s[vertexIndex2].x + tMat.col2.y * vert2s[vertexIndex2].y)

         //var separation = b2Math.b2Dot( b2Math.SubtractVV( v2, v1 ) , normal);
         v2X -= v1X;
         v2Y -= v1Y;
         //var separation = b2Math.b2Dot( v2 , normal);
         var separation = v2X * normalX + v2Y * normalY;
         return separation;
      },

      FindMaxSeparation: function(edgeIndex /*int ptr*/, poly1, poly2, conservative) {
         var count1 = poly1.m_vertexCount;

         // Vector pointing from the origin of poly1 to the origin of poly2.
         //var d = b2Math.SubtractVV( poly2.m_position, poly1.m_position );
         var dX = poly2.m_position.x - poly1.m_position.x;
         var dY = poly2.m_position.y - poly1.m_position.y;

         //var dLocal1 = b2Math.b2MulTMV(poly1.m_R, d);
         var dLocal1X = (dX * poly1.m_R.col1.x + dY * poly1.m_R.col1.y);
         var dLocal1Y = (dX * poly1.m_R.col2.x + dY * poly1.m_R.col2.y);

         // Get support vertex hint for our search
         var edge = 0;
         var maxDot = -Number.MAX_VALUE;
         for (var i = 0; i < count1; ++i)
         {
            //var dot = b2Math.b2Dot(poly.m_normals[i], dLocal1);
            var dot = (poly1.m_normals[i].x * dLocal1X + poly1.m_normals[i].y * dLocal1Y);
            if (dot > maxDot)
            {
               maxDot = dot;
               edge = i;
            }
         }

         // Get the separation for the edge normal.
         var s = b2Collision.EdgeSeparation(poly1, edge, poly2);
         if (s > 0.0 && conservative == false)
         {
            return s;
         }

         // Check the separation for the neighboring edges.
         var prevEdge = edge - 1 >= 0 ? edge - 1 : count1 - 1;
         var sPrev = b2Collision.EdgeSeparation(poly1, prevEdge, poly2);
         if (sPrev > 0.0 && conservative == false)
         {
            return sPrev;
         }

         var nextEdge = edge + 1 < count1 ? edge + 1 : 0;
         var sNext = b2Collision.EdgeSeparation(poly1, nextEdge, poly2);
         if (sNext > 0.0 && conservative == false)
         {
            return sNext;
         }

         // Find the best edge and the search direction.
         var bestEdge = 0;
         var bestSeparation;
         var increment = 0;
         if (sPrev > s && sPrev > sNext)
         {
            increment = -1;
            bestEdge = prevEdge;
            bestSeparation = sPrev;
         }
         else if (sNext > s)
         {
            increment = 1;
            bestEdge = nextEdge;
            bestSeparation = sNext;
         }
         else
         {
            // pointer out
            edgeIndex[0] = edge;
            return s;
         }

         while (true)
         {

            if (increment == -1)
               edge = bestEdge - 1 >= 0 ? bestEdge - 1 : count1 - 1;
            else
               edge = bestEdge + 1 < count1 ? bestEdge + 1 : 0;

            s = b2Collision.EdgeSeparation(poly1, edge, poly2);
            if (s > 0.0 && conservative == false)
            {
               return s;
            }

            if (s > bestSeparation)
            {
               bestEdge = edge;
               bestSeparation = s;
            }
            else
            {
               break;
            }
         }

         // pointer out
         edgeIndex[0] = bestEdge;
         return bestSeparation;
      },

      FindIncidentEdge: function(c, poly1, edge1, poly2) {
         var count1 = poly1.m_vertexCount;
         var vert1s = poly1.m_vertices;
         var count2 = poly2.m_vertexCount;
         var vert2s = poly2.m_vertices;

         // Get the vertices associated with edge1.
         var vertex11 = edge1;
         var vertex12 = edge1 + 1 == count1 ? 0 : edge1 + 1;

         // Get the normal of edge1.
         var tVec = vert1s[vertex12];
         //var normal1Local1 = b2Math.b2CrossVF( b2Math.SubtractVV( vert1s[vertex12], vert1s[vertex11] ), 1.0);
         var normal1Local1X = tVec.x;
         var normal1Local1Y = tVec.y;
         tVec = vert1s[vertex11];
         normal1Local1X -= tVec.x;
         normal1Local1Y -= tVec.y;
         var tX = normal1Local1X;
         normal1Local1X = normal1Local1Y;
         normal1Local1Y = -tX;
         // ^^^^ normal1Local1.CrossVF(1.0);

         var invLength = 1.0 / Math.sqrt(normal1Local1X*normal1Local1X + normal1Local1Y*normal1Local1Y);
         normal1Local1X *= invLength;
         normal1Local1Y *= invLength;
         // ^^^^normal1Local1.Normalize();
         //var normal1 = b2Math.b2MulMV(poly1.m_R, normal1Local1);
         var normal1X = normal1Local1X;
         var normal1Y = normal1Local1Y;

         tX = normal1X;
         var tMat = poly1.m_R;
         normal1X = tMat.col1.x * tX + tMat.col2.x * normal1Y;
         normal1Y = tMat.col1.y * tX + tMat.col2.y * normal1Y;
         // ^^^^ normal1.MulM(poly1.m_R);

         //var normal1Local2 = b2Math.b2MulTMV(poly2.m_R, normal1);
         var normal1Local2X = normal1X;
         var normal1Local2Y = normal1Y;
         tMat = poly2.m_R;
         tX = normal1Local2X * tMat.col1.x + normal1Local2Y * tMat.col1.y;
         normal1Local2Y = normal1Local2X * tMat.col2.x + normal1Local2Y * tMat.col2.y;
         normal1Local2X = tX;
         // ^^^^ normal1Local2.MulTM(poly2.m_R);

         // Find the incident edge on poly2.
         var vertex21 = 0;
         var vertex22 = 0;
         var minDot = Number.MAX_VALUE;
         for (var i = 0; i < count2; ++i)
         {
            var i1 = i;
            var i2 = i + 1 < count2 ? i + 1 : 0;

            //var normal2Local2 = b2Math.b2CrossVF( b2Math.SubtractVV( vert2s[i2], vert2s[i1] ), 1.0);
            tVec = vert2s[i2];
            var normal2Local2X = tVec.x;
            var normal2Local2Y = tVec.y;
            tVec = vert2s[i1];
            normal2Local2X -= tVec.x;
            normal2Local2Y -= tVec.y;
            tX = normal2Local2X;
            normal2Local2X = normal2Local2Y;
            normal2Local2Y = -tX;
            // ^^^^ normal2Local2.CrossVF(1.0);

            invLength = 1.0 / Math.sqrt(normal2Local2X*normal2Local2X + normal2Local2Y*normal2Local2Y);
            normal2Local2X *= invLength;
            normal2Local2Y *= invLength;
            // ^^^^ normal2Local2.Normalize();

            //var dot = b2Math.b2Dot(normal2Local2, normal1Local2);
            var dot = normal2Local2X * normal1Local2X + normal2Local2Y * normal1Local2Y;
            if (dot < minDot)
            {
               minDot = dot;
               vertex21 = i1;
               vertex22 = i2;
            }
         }

         var tClip;
         // Build the clip vertices for the incident edge.
         tClip = c[0];
         //tClip.v = b2Math.AddVV(poly2.m_position, b2Math.b2MulMV(poly2.m_R, vert2s[vertex21]));
         tVec = tClip.v;
         tVec.SetV(vert2s[vertex21]);
         tVec.MulM(poly2.m_R);
         tVec.Add(poly2.m_position);

         tClip.id.features.referenceFace = edge1;
         tClip.id.features.incidentEdge = vertex21;
         tClip.id.features.incidentVertex = vertex21;

         tClip = c[1];
         //tClip.v = b2Math.AddVV(poly2.m_position, b2Math.b2MulMV(poly2.m_R, vert2s[vertex22]));
         tVec = tClip.v;
         tVec.SetV(vert2s[vertex22]);
         tVec.MulM(poly2.m_R);
         tVec.Add(poly2.m_position);
         tClip.id.features.referenceFace = edge1;
         tClip.id.features.incidentEdge = vertex21;
         tClip.id.features.incidentVertex = vertex22;
      },
      
      b2CollidePoly: function(manifold, polyA, polyB, conservative) {
         manifold.pointCount = 0;

         var edgeA = 0;
         var edgeAOut = [edgeA];
         var separationA = b2Collision.FindMaxSeparation(edgeAOut, polyA, polyB, conservative);
         edgeA = edgeAOut[0];
         if (separationA > 0.0 && conservative == false)
            return;

         var edgeB = 0;
         var edgeBOut = [edgeB];
         var separationB = b2Collision.FindMaxSeparation(edgeBOut, polyB, polyA, conservative);
         edgeB = edgeBOut[0];
         if (separationB > 0.0 && conservative == false)
            return;

         var poly1;
         var poly2;
         var edge1 = 0;
         var flip = 0;
         var k_relativeTol = 0.98;
         var k_absoluteTol = 0.001;

         // TODO_ERIN use "radius" of poly for absolute tolerance.
         if (separationB > k_relativeTol * separationA + k_absoluteTol)
         {
            poly1 = polyB;
            poly2 = polyA;
            edge1 = edgeB;
            flip = 1;
         }
         else
         {
            poly1 = polyA;
            poly2 = polyB;
            edge1 = edgeA;
            flip = 0;
         }

         var incidentEdge = [new ClipVertex(), new ClipVertex()];
         b2Collision.FindIncidentEdge(incidentEdge, poly1, edge1, poly2);

         var count1 = poly1.m_vertexCount;
         var vert1s = poly1.m_vertices;

         var v11 = vert1s[edge1];
         var v12 = edge1 + 1 < count1 ? vert1s[edge1+1] : vert1s[0];

         //var dv = b2Math.SubtractVV(v12, v11);
         var dvX = v12.x - v11.x;
         var dvY = v12.y - v11.y;

         //var sideNormal = b2Math.b2MulMV(poly1.m_R, b2Math.SubtractVV(v12, v11));
         var sideNormalX = v12.x - v11.x;
         var sideNormalY = v12.y - v11.y;

         var tX = sideNormalX;
         var tMat = poly1.m_R;
         sideNormalX = tMat.col1.x * tX + tMat.col2.x * sideNormalY;
         sideNormalY = tMat.col1.y * tX + tMat.col2.y * sideNormalY;
         // ^^^^ sideNormal.MulM(poly1.m_R);

         var invLength = 1.0 / Math.sqrt(sideNormalX*sideNormalX + sideNormalY*sideNormalY);
         sideNormalX *= invLength;
         sideNormalY *= invLength;
         // ^^^^ sideNormal.Normalize();

         //var frontNormal = b2Math.b2CrossVF(sideNormal, 1.0);
         var frontNormalX = sideNormalX;
         var frontNormalY = sideNormalY;
         tX = frontNormalX;
         frontNormalX = frontNormalY;
         frontNormalY = -tX;
         // ^^^^ frontNormal.CrossVF(1.0);

         // Expanded for performance
         //v11 = b2Math.AddVV(poly1.m_position, b2Math.b2MulMV(poly1.m_R, v11));
         var v11X = v11.x;
         var v11Y = v11.y;
         tX = v11X;
         tMat = poly1.m_R;
         v11X = tMat.col1.x * tX + tMat.col2.x * v11Y;
         v11Y = tMat.col1.y * tX + tMat.col2.y * v11Y;
         // ^^^^ v11.MulM(poly1.m_R);
         v11X += poly1.m_position.x;
         v11Y += poly1.m_position.y;
         //v12 = b2Math.AddVV(poly1.m_position, b2Math.b2MulMV(poly1.m_R, v12));
         var v12X = v12.x;
         var v12Y = v12.y;
         tX = v12X;
         tMat = poly1.m_R;
         v12X = tMat.col1.x * tX + tMat.col2.x * v12Y;
         v12Y = tMat.col1.y * tX + tMat.col2.y * v12Y;
         // ^^^^ v12.MulM(poly1.m_R);
         v12X += poly1.m_position.x;
         v12Y += poly1.m_position.y;

         //var frontOffset = b2Math.b2Dot(frontNormal, v11);
         var frontOffset = frontNormalX * v11X + frontNormalY * v11Y;
         //var sideOffset1 = -b2Math.b2Dot(sideNormal, v11);
         var sideOffset1 = -(sideNormalX * v11X + sideNormalY * v11Y);
         //var sideOffset2 = b2Math.b2Dot(sideNormal, v12);
         var sideOffset2 = sideNormalX * v12X + sideNormalY * v12Y;

         // Clip incident edge against extruded edge1 side edges.
         var clipPoints1 = [new ClipVertex(), new ClipVertex()];
         var clipPoints2 = [new ClipVertex(), new ClipVertex()];

         var np = 0;

         // Clip to box side 1
         b2Collision.b2CollidePolyTempVec.Set(-sideNormalX, -sideNormalY);
         np = b2Collision.ClipSegmentToLine(clipPoints1, incidentEdge, b2Collision.b2CollidePolyTempVec, sideOffset1);

         if (np < 2)
            return;

         // Clip to negative box side 1
         b2Collision.b2CollidePolyTempVec.Set(sideNormalX, sideNormalY);
         np = b2Collision.ClipSegmentToLine(clipPoints2, clipPoints1,  b2Collision.b2CollidePolyTempVec, sideOffset2);

         if (np < 2)
            return;

         // Now clipPoints2 contains the clipped points.
         if (flip){
            manifold.normal.Set(-frontNormalX, -frontNormalY);
         }
         else{
            manifold.normal.Set(frontNormalX, frontNormalY);
         }
         // ^^^^ manifold.normal = flip ? frontNormal.Negative() : frontNormal;

         var pointCount = 0;
         for (var i = 0; i < b2Settings.b2_maxManifoldPoints; ++i)
         {
            //var separation = b2Math.b2Dot(frontNormal, clipPoints2[i].v) - frontOffset;
            var tVec = clipPoints2[i].v;
            var separation = (frontNormalX * tVec.x + frontNormalY * tVec.y) - frontOffset;

            if (separation <= 0.0 || conservative == true)
            {
               var cp = manifold.points[ pointCount ];
               cp.separation = separation;
               cp.position.SetV( clipPoints2[i].v );
               cp.id.Set( clipPoints2[i].id );
               cp.id.features.flip = flip;
               ++pointCount;
            }
         }

         manifold.pointCount = pointCount;
      },

      b2CollideCircle: function(manifold, circle1, circle2, conservative) {
         manifold.pointCount = 0;

         //var d = b2Math.SubtractVV(circle2.m_position, circle1.m_position);
         var dX = circle2.m_position.x - circle1.m_position.x;
         var dY = circle2.m_position.y - circle1.m_position.y;
         //var distSqr = b2Math.b2Dot(d, d);
         var distSqr = dX * dX + dY * dY;
         var radiusSum = circle1.m_radius + circle2.m_radius;
         if (distSqr > radiusSum * radiusSum && conservative == false)
         {
            return;
         }

         var separation;
         if (distSqr < Number.MIN_VALUE)
         {
            separation = -radiusSum;
            manifold.normal.Set(0.0, 1.0);
         }
         else
         {
            var dist = Math.sqrt(distSqr);
            separation = dist - radiusSum;
            var a = 1.0 / dist;
            manifold.normal.x = a * dX;
            manifold.normal.y = a * dY;
         }

         manifold.pointCount = 1;
         var tPoint = manifold.points[0];
         tPoint.id.set_key(0);
         tPoint.separation = separation;
         //tPoint.position = b2Math.SubtractVV(circle2.m_position, b2Math.MulFV(circle2.m_radius, manifold.normal));
         tPoint.position.x = circle2.m_position.x - (circle2.m_radius * manifold.normal.x);
         tPoint.position.y = circle2.m_position.y - (circle2.m_radius * manifold.normal.y);
      },
      
      b2CollidePolyAndCircle: function(manifold, poly, circle, conservative) {
         manifold.pointCount = 0;
         var tPoint;

         var dX;
         var dY;

         // Compute circle position in the frame of the polygon.
         //var xLocal = b2Math.b2MulTMV(poly.m_R, b2Math.SubtractVV(circle.m_position, poly.m_position));
         var xLocalX = circle.m_position.x - poly.m_position.x;
         var xLocalY = circle.m_position.y - poly.m_position.y;
         var tMat = poly.m_R;
         var tX = xLocalX * tMat.col1.x + xLocalY * tMat.col1.y;
         xLocalY = xLocalX * tMat.col2.x + xLocalY * tMat.col2.y;
         xLocalX = tX;

         var dist;

         // Find the min separating edge.
         var normalIndex = 0;
         var separation = -Number.MAX_VALUE;
         var radius = circle.m_radius;
         for (var i = 0; i < poly.m_vertexCount; ++i)
         {
            //var s = b2Math.b2Dot(poly.m_normals[i], b2Math.SubtractVV(xLocal, poly.m_vertices[i]));
            var s = poly.m_normals[i].x * (xLocalX-poly.m_vertices[i].x) + poly.m_normals[i].y * (xLocalY-poly.m_vertices[i].y);
            if (s > radius)
            {
               // Early out.
               return;
            }

            if (s > separation)
            {
               separation = s;
               normalIndex = i;
            }
         }

         // If the center is inside the polygon ...
         if (separation < Number.MIN_VALUE)
         {
            manifold.pointCount = 1;
            //manifold.normal = b2Math.b2MulMV(poly.m_R, poly.m_normals[normalIndex]);
            var tVec = poly.m_normals[normalIndex];
            manifold.normal.x = tMat.col1.x * tVec.x + tMat.col2.x * tVec.y;
            manifold.normal.y = tMat.col1.y * tVec.x + tMat.col2.y * tVec.y;

            tPoint = manifold.points[0];
            tPoint.id.features.incidentEdge = normalIndex;
            tPoint.id.features.incidentVertex = b2Collision.b2_nullFeature;
            tPoint.id.features.referenceFace = b2Collision.b2_nullFeature;
            tPoint.id.features.flip = 0;
            tPoint.position.x = circle.m_position.x - radius * manifold.normal.x;
            tPoint.position.y = circle.m_position.y - radius * manifold.normal.y;
            //tPoint.position = b2Math.SubtractVV(circle.m_position , b2Math.MulFV(radius , manifold.normal));
            tPoint.separation = separation - radius;
            return;
         }

         // Project the circle center onto the edge segment.
         var vertIndex1 = normalIndex;
         var vertIndex2 = vertIndex1 + 1 < poly.m_vertexCount ? vertIndex1 + 1 : 0;
         //var e = b2Math.SubtractVV(poly.m_vertices[vertIndex2] , poly.m_vertices[vertIndex1]);
         var eX = poly.m_vertices[vertIndex2].x - poly.m_vertices[vertIndex1].x;
         var eY = poly.m_vertices[vertIndex2].y - poly.m_vertices[vertIndex1].y;
         //var length = e.Normalize();
         var length = Math.sqrt(eX*eX + eY*eY);
         eX /= length;
         eY /= length;

         // If the edge length is zero ...
         if (length < Number.MIN_VALUE)
         {
            //d = b2Math.SubtractVV(xLocal , poly.m_vertices[vertIndex1]);
            dX = xLocalX - poly.m_vertices[vertIndex1].x;
            dY = xLocalY - poly.m_vertices[vertIndex1].y;
            //dist = d.Normalize();
            dist = Math.sqrt(dX*dX + dY*dY);
            dX /= dist;
            dY /= dist;
            if (dist > radius)
            {
               return;
            }

            manifold.pointCount = 1;
            //manifold.normal = b2Math.b2MulMV(poly.m_R, d);
            manifold.normal.Set(tMat.col1.x * dX + tMat.col2.x * dY, tMat.col1.y * dX + tMat.col2.y * dY);
            tPoint = manifold.points[0];
            tPoint.id.features.incidentEdge = b2Collision.b2_nullFeature;
            tPoint.id.features.incidentVertex = vertIndex1;
            tPoint.id.features.referenceFace = b2Collision.b2_nullFeature;
            tPoint.id.features.flip = 0;
            //tPoint.position = b2Math.SubtractVV(circle.m_position , b2Math.MulFV(radius , manifold.normal));
            tPoint.position.x = circle.m_position.x - radius * manifold.normal.x;
            tPoint.position.y = circle.m_position.y - radius * manifold.normal.y;
            tPoint.separation = dist - radius;
            return;
         }

         // Project the center onto the edge.
         //var u = b2Math.b2Dot(b2Math.SubtractVV(xLocal , poly.m_vertices[vertIndex1]) , e);
         var u = (xLocalX-poly.m_vertices[vertIndex1].x) * eX + (xLocalY-poly.m_vertices[vertIndex1].y) * eY;

         tPoint = manifold.points[0];
         tPoint.id.features.incidentEdge = b2Collision.b2_nullFeature;
         tPoint.id.features.incidentVertex = b2Collision.b2_nullFeature;
         tPoint.id.features.referenceFace = b2Collision.b2_nullFeature;
         tPoint.id.features.flip = 0;

         var pX, pY;
         if (u <= 0.0)
         {
            pX = poly.m_vertices[vertIndex1].x;
            pY = poly.m_vertices[vertIndex1].y;
            tPoint.id.features.incidentVertex = vertIndex1;
         }
         else if (u >= length)
         {
            pX = poly.m_vertices[vertIndex2].x;
            pY = poly.m_vertices[vertIndex2].y;
            tPoint.id.features.incidentVertex = vertIndex2;
         }
         else
         {
            //p = b2Math.AddVV(poly.m_vertices[vertIndex1] , b2Math.MulFV(u, e));
            pX = eX * u + poly.m_vertices[vertIndex1].x;
            pY = eY * u + poly.m_vertices[vertIndex1].y;
            tPoint.id.features.incidentEdge = vertIndex1;
         }

         //d = b2Math.SubtractVV(xLocal , p);
         dX = xLocalX - pX;
         dY = xLocalY - pY;
         //dist = d.Normalize();
         dist = Math.sqrt(dX*dX + dY*dY);
         dX /= dist;
         dY /= dist;
         if (dist > radius)
         {
            return;
         }

         manifold.pointCount = 1;
         //manifold.normal = b2Math.b2MulMV(poly.m_R, d);
         manifold.normal.Set(tMat.col1.x * dX + tMat.col2.x * dY, tMat.col1.y * dX + tMat.col2.y * dY);
         //tPoint.position = b2Math.SubtractVV(circle.m_position , b2Math.MulFV(radius , manifold.normal));
         tPoint.position.x = circle.m_position.x - radius * manifold.normal.x;
         tPoint.position.y = circle.m_position.y - radius * manifold.normal.y;
         tPoint.separation = dist - radius;
      },
      
      b2TestOverlap: function(a, b) {
         var t1 = b.minVertex;
         var t2 = a.maxVertex;
         //d1 = b2Math.SubtractVV(b.minVertex, a.maxVertex);
         var d1X = t1.x - t2.x;
         var d1Y = t1.y - t2.y;
         //d2 = b2Math.SubtractVV(a.minVertex, b.maxVertex);
         t1 = a.minVertex;
         t2 = b.maxVertex;
         var d2X = t1.x - t2.x;
         var d2Y = t1.y - t2.y;

         if (d1X > 0.0 || d1Y > 0.0)
            return false;

         if (d2X > 0.0 || d2Y > 0.0)
            return false;

         return true;
      },

		resolved: function() {
			b2Collision.b2CollidePolyTempVec = new b2Vec2();
		},
		
      b2CollidePolyTempVec: null
		

   });
   
   return b2Collision;
   
});
